The inventions covered in this application relate to Ear Buds, In Ear Monitors, Hearing Aids and all related personal listening devices (hereafter collectively referred to as “earbuds”).
More specifically, they relate to high fidelity earbud hearing protection and health while affording enhanced sound quality, isolation, fit, aesthetics, overall customizability characteristics, Bluetooth connectivity, the reduction of event-based hearing damage/noise pollution through their use at concerts, sports events, etc., live broadcast and location based syncing of at-event wireless audio streaming to smartphones and similar WiFi or Bluetooth devices, —as well as a novel displacement-based digital audio compression algorithm which electronically mitigates premature triggering of the acoustic reflex thereby allowing lower in-ear volumes to sound louder than conventional couplings which are known to cause hearing loss.
Earbuds provide utility as portable and private audio devices and are sometimes improperly employed to inadequately isolate the user from external sounds while listening to in/on-ear audio [U.S. Pat. Nos. 4,239,945; 4,742,887; 8,638,971B2]. Utilizing an ear tip, ear mold or ear cushion, earbuds partially or wholly seal the ear canal in an effort to increase the isolation from external sounds as well as increase the retention of both the device and the amplified sound within or around the ear. However, formal studies show their regular use leads directly to permanent hearing damage.
Large, high intensity transducer membrane excursions (i.e. the vibratory back and forth movements of the speaker diaphragm) are necessary for the audible propagation of acoustic sound waves by earbuds. However, under partially or wholly sealed in-ear conditions, these relatively huge motions result in harmful oscillating pneumatic air pressures within the enclosed canal volume which overly impinge a significant percentage of the speaker diaphragm excursions directly onto the delicate and highly sensitive tympanic membrane, thereby overwhelming the natural compliance of the ear drum. Typical earbud/headphone speaker excursions range from microns to millimeters while normal tympanic membrane excursions range from only 100 to 250 nanometers, or roughly 1000 times smaller than typical speaker excursions.
Additionally, broadband, pneumatically coupled, in-ear sound pressures prematurely trigger the acoustic reflex, wherein, the tensor tympani muscle tightens the tympanic membrane, and the stapedius muscle pulls on and stiffens the ossicular chain, drawing the stapes away from the cochlea's oval window. This premature triggering often occurs as low as 60 dB when the ear canal is partially or wholly sealed instead of its typical audiologically established 88-90 dB threshold for an open ear canal.
Under these conditions, the net result of this premature triggering of the acoustic reflex is that sound waves are far less efficiently passed through to the inner ear, while their broadband pneumatic components continue to overly impinge on the tympanic membrane. Overall listening volumes are significantly less audible. The typical user response to this involuntary reflex is to turn the audio volume up much higher, resulting in international efforts to advise users of the dangers attendant upon listening to earbuds at excessive volume levels. This situation continues quite unresolved, resulting in habitual, overwhelming pressures on the tympanic membrane and leading to dramatic worldwide increases in permanent hearing loss.
The occlusion effect—i.e. bone conduction of one's own internal voice and body sounds resonating within the sealed ear canal (including transduction of external sound waves through vibrating bones, fluids, body cavities, tissues and in-ear devices) is the result of displacement based oscillating pneumatic air pressures from vibrating in ear surfaces which are then overly impinged onto both the tympanic membrane and the middle ear: sounds which are normally inaudible under unsealed conditions are pneumatically amplified as much as 1000 times (60 dB) over their normally unsealed volume levels. For example, one is able to easily hear the normally inaudible internal sounds of their own jaw motions or blood pumping amplified many times by simply plugging and sealing their ears with their fingers or foam ear plugs.
The confining of acoustically driven mechanical surface vibrations into relatively small, trapped volumes such as the ear canal results in unintended pneumatic displacement based in-ear acoustical amplifications similar to the intentional amplifications provided by stethoscopes, woodwinds, brass instruments, etc. All of these instruments gain their intended amplification through the principle of the pneumatic coupling of enclosed displacement based pneumatic pressures. This principle results in hearing loss when unwittingly applied to the ear because it is masked by the acoustic reflex and unrealized by the listener over time.
As described above, when the outer portion of the ear canal is sealed, in-ear sounds are significantly amplified by their aforementioned transformation into oscillatory pneumatic pressures, regardless of whether or not an active audio speaker is also present. However, this phenomena becomes greatly exaggerated when the normal diaphragm excursions of earbud speakers are introduced concurrent with mandibular (jawbone) deformations of the occluded ear canal walls such as those which occur during talking, singing, chewing, and yawning, —since all of these common physiological conditions independently create large increases in pneumatic in-ear pressures when the ear canal surfaces are exposed yet externally sealed and their accumulating pressures are thereby kept from immediately equalizing with normal external barometric pressure.
When earbuds conventionally seal the ear canal, these physiological conditions compound with transducer based in-ear sound pressures and together, dramatically increase the overall oscillating pneumatic pressure on the tympanic membrane by as much as 1 kPa or more. As already observed, this condition prematurely triggers the acoustic reflex, thereby demanding excessive listening volumes leading to hearing loss.
Conventional solutions to reducing the occlusion effect while wearing earbuds involve the introduction of leaks or vents into the chamber in front of the speaker. These leaks are acoustic as well as pneumatic and result in reduced volume levels, degraded bass frequency response and inadequate isolation and thereby demand higher listening volumes since the speaker is now driving a greatly enlarged or even unenclosed chamber. Here again, the typical user response has been to resort to excessive listening volumes. Unavoidable, accidental improved sealing conditions such as occur when shoving the device in deeper or leaning the ear containing the earbud up against a pillow or headrest often results in extremely high volumes which create pain and hearing loss before the person can easily respond, since the acoustic reflex greatly masks the condition.
Additionally, many conventional acoustic ear-coupling approaches use a hard, smooth surface for the ear tip or ear mold. Under conditions of mandibular deformation, such a surface forms an inconsistent seal, thus an intermittent leak between the coupler and the ear canal is inevitable, resulting in inconsistent coupling, degraded sound quality and inadequate isolation.
Some earbud designs utilize screened airflow channels independent of ear tip design to vent the front chamber air within the speaker housing to the outside, barometric pressure air. The Apple earbud design of 2013, for example, incorporates both venting methods [U.S. Pat. No. D691,594S] of the screened airflow channels and the hard, smooth ear tip surface. As described above, these solutions demand increased listening volumes.
Under wholly or partially sealed conditions, pneumatic pressures impede the motion of an earbud speaker. As the speaker moves within a sealed chamber, it inadvertently and variably compresses the trapped air into a smaller volume. As air is semi-incompressible, it resists, preventing the speaker from performing its intended linear excursion. Unlike unsealed conditions, the pressures created are nonlinear. Thusly impeded, the speaker exhibits slower transient responses, generating muddled, damped, lower quality sounds, which are especially nonlinear in the bass frequencies. Additionally, the natural performance of the Helmholtz resonance of the ear canal is significantly degraded.
In contrast, small air vents or screens are routinely employed in the back chamber of earbud speakers to allow similarly compressed air to escape and new air to flow in during rarefactions, thereby allowing the speaker to move more freely.
Under sealed conditions, the premature triggering of the acoustic reflex results in the stiffened compliance of the tympanic membrane variably determining the level of impedance on the speaker diaphragm facing the ear canal chamber, contributing significantly to the nonlinear functioning of both the speaker diaphragm and the tympanic membrane and thereby further degrading audio performance.
The aforementioned open-air pressure vents and leaks also act as acoustic vents. Employed in the chamber comprising the ear canal, sound amplitude and quality, particularly in the lower spectral regions, is significantly reduced with their use and listeners once again choose high audio volumes to recover the signal.
The Ambrose Diaphonic Ear Lens (ADEL) In-Ear Bubble invented by Stephen Ambrose (U.S. Pat. Nos. 8,340,310 B2 and 8,391,534 B2) significantly mitigates the shortcomings of conventional coupling systems such as common ear molds and ear tips. The inflatable ADEL ear tip is made of a highly flexible material, which when inflated, forms an effective, consistent and comfortable acoustic seal with the ear canal, despite physical exercise and mandibular deformations. The pressure exerted on the ear canal is sufficiently minimal that the presence of an ADEL disappears from the user's perception.
The ADEL is more compliant than the tympanic membrane by several orders of magnitude and is able to both absorb pneumatic pressures from within the sealed canal and reflect a greatly reduced return wave back onto the tympanic membrane. Unwanted reflections and resonances are substantially reduced.
The extremely low mass, low impedance mechanical excursion response of the ADEL membrane is much faster than both the speaker diaphragm and the tympanic membrane and results in ideal (extremely fast and high resolution) in-ear frequency/transient/dynamic range response—therefore significantly improving the performance and sound quality of any speaker mechanically coupled to the ear.
The inflatable ADEL very easily and comfortably enters, fills and displaces the full volume of the ear canal and thereby significantly reduces the occlusion effect. The tympanic membrane receives a more natural and healthy level of sound, the stapedius reflex does not prematurely trigger, the occlusion effect is minimized or removed, and the user perceives a much improved quality of sound throughout their listening experience without having to resort to excessive sound levels.
The passive, un-inflated ADEL absorbs the aforementioned pneumatic components of enclosed in-ear sound waves and thereby effectively lessens the occlusion effect as well as all the other unwanted conditions described above.
Many earbuds on the market are advertised as providing sound isolation. The isolation from exterior sounds is achieved by sealing the ear with unattractive, uncomfortable and noncompliant ear molds or over-sized foam or mushroom-shaped ear tips or with moldable materials such as self-curing silicones or wax.
In addition to being uncomfortable, conventional coupling methods often become dislodged, variably leak or introduce the occlusion effect (the unwanted booming bass of one's own voice), provide inadequate and inconsistent isolation/acoustic sealing and degrade the quality of in-ear acoustics by damping, exaggerating, muffling and blurring the source sound. Dedicated, sound isolating earbuds also operate under an all-or-nothing premise. The user must dislodge them to hear external sounds and replace them to hear the speaker and block off external sound.
Most available earbuds fit their users poorly and uncomfortably and their aesthetics tend to come at sacrifices to other earbud qualities. The diameter of the coupling element inserted into the ear may be too small or large, the element may be too short or angled incorrectly to match the user's ear topology. Ear couplers may be designed to be intentionally too large such as the foam plug or mushroom-cap tips to create a more complete seal and to resist falling out with motion. The oversized ear tips place a high pressure against the ear canal flesh and quickly become uncomfortable. Some models are designed with uncomfortable, non-customizable stabilizers or ear hangars in an attempt to take the weight of the earbud off the ear canal and improve stability; users commonly choose from a range of differently sized foam or mushroom-cap ear tips. Modifications of the length, direction, and curvature of the ear tips or overall custom fits are not available options to the general earbud consumer. While many earbuds are advertised as providing sound isolation, none are marketed for their ability to provide the user environmental awareness, and further none provide directionality-sensitivity. This creates a safety problem wherein the user is unable to hear warning sounds, other people, or other audible indications of impending harm.
The original in-ear monitor (IEM) invented by Stephen Ambrose in the 1960's and used for performances by musicians was the precursor for modern earbuds. IEMs tend to have customized, molded couplers that exactly fit performers' ears to attain the highest degree of isolation. These IEMs are uncomfortable in as much as the ear mold materials are rigid, fit tightly and do not flex with normal jaw motions; create very high levels of occlusion; and are unattractive as they tend to fill the visible ear canal with a vaguely flesh-colored plastic or silicon. An early version of Mr. Ambrose's IEM functioned as a portable listening device, a hearing aid and as functional jewelry [U.S. Pat. No. 4,852,177; 1989]. It employed a secondary acoustic path that vented pressures on the ear to a correct location in the earphone and prohibited a feedback cycle with the microphone that passed environmental sound into the sealed ear. These IEMs contributed less to hearing loss through this patented method by partially mitigating the pneumatic effects of sound constrained within the relatively small, trapped volumes of the sealed ear canal.
Most components that comprise conventional earbuds, whether they are custom-made or commercial, off-the-shelf products are not modifiable by the user. The user must choose at the time of purchase the set of earbud appearance, fit, quality and sound isolation that they are able to buy. Any desired variations require the purchase of another pair of earbuds.
Current Bluetooth connected earbuds are limited in both power and resolution. Bluetooth technology passes a low-resolution, compressed, digitized signal that degrades both the temporal resolution and the dynamic range of streamed music. Its receiver system can be a heavy user of power that requires frequent recharging. Many manufacturers opt to use a lower power version to minimize user frustrations but that comes at the cost of even less power for speaker operations. Speakers are then chosen that can only operate within remaining power budget, which further reduces the potential dynamic range of music.
Sound pressure levels of amplified live musical performances are commonly set at excessive volumes in an effort to produce a sensational experience for attendees. Because of the need for the sound emanating from speakers placed at the front of the stage to be loud enough to reach audiences in the back of the venue, attendees located closer to the stage are often subjected to deafening volumes for many hours. Such overstimulation triggers TTS (Temporary Threshold Shift wherein the listener's hearing sensitivity is involuntarily reduced) amongst the attendees, which then demands louder volumes to create the same sensation.
A resultant cacophony of competing sound sources further escalates these amplified sound pressure levels. In addition to highly amplified stage volumes, crowd noise, pyro technical explosions, etc., concert-goers also experience significant levels of physically transduced sounds (vibrations that impact and pass through the body).
These competing sound sources reflect off the walls, ceilings or other surfaces containing or surrounding the venue. In an attempt to cut through this confusion, amplified volumes are often pushed even louder.
In Ear Monitors were invented by Stephen Ambrose in 1965 and developed in the 70s with the help of Stevie Wonder to allow performers to hear their own music on stage and isolate away the competing sounds with the same quality they enjoy when using headphones in recording studios.
However, because these devices can create pneumatic pressures which trigger the acoustic or stapedius reflex and add the booming occlusion affect one's voice and music, they tend to subject the performers to excessive in-ear volume levels and must be dislodged or removed in order to hear ambient sounds. They are usually embodied in ear molds, which are uncomfortable and look unattractive. The isolation they offer is not optimum for all situations.
Auditory damage to both the performer's and the attendee's hearing caused by excessive volumes at musical events is well understood and documented. Civic regulations on noise pollution, timings and locations of events are continuing to limit venue opportunities for hosting a full-featured musical performance.
Currently available earbuds have limited ability to mitigate the excessive noise levels of amplified musical events. On the contrary, they tend to add their own inherently excessive listening levels to the excessive volumes present at the amplified even, thereby compounding the risk of hearing loss.
Conventional hearing protectors muffle the sound, are uncomfortable and can create excessive in-ear pressures. Additionally, occupants of areas neighboring a venue cannot practically or ethically be required to wear hearing protection devices.
Conventional in ear monitors do not allow an adjustable mixture of both the ambient and the electronically broadcast renditions of their performance. Often performers can be seen wearing only one IEM or hanging the other over their shoulder in order to hear their surrounding environment.
When worn out in the audience, IEMs sound far better than the over-amplified concert despite not being synchronized with the amplified sound coming off the stage. However, the further one is from the stage, the greater the lag between the broadcast sound and the amplified sound emanating from the stage speakers.
The capability of synchronizing these two sound sources and allowing for user-adjustable volumes and mixtures between the two (as allowed by the novel invention described herein) has not been possible before now.
Prior attempts at broadcast performances used a single broadcast source using radio transmissions and timing delays were incurred by the difference in the speed of sound (live music) versus the speed of light (radio transmissions). In a large enough venue, attendees receive the radio transmission before the live music reached them, which creates an untenable timing gap.
Conventional earbuds degrade and muffle the amplified concert sound as well as the broadcast in-ear speaker sound due to occlusion, speaker impedance mismatch with the tympanic membrane and the aforementioned and resultant over-stimulation of the acoustic reflex. This creates a disruptive quality gap when trying to simultaneously listen to a broadcast and a live performance. Excessive volumes of both audio sources are additive and the risk of hearing loss is increased even further.
Amplitude-based compression algorithms that limit the dynamic (soft to loud) range of sounds produced from an audio system are commonly available. One example applies to television ads. The creators or broadcasters of television advertisements often use amplitude based dynamic range compression to set the overall audio volume of their advertisements at a higher level than the programs within which they're aired to draw viewers' attention to them. Counteracting software exists that reduces those sound volumes back in line with the programs. Similar sound reduction software algorithms, which are generally known as digital dynamic range compression, are applied to audio systems, MP3 players and smartphones for listening to music more safely.
These existing algorithms are amplitude-based and are set at ratios of sound level volumes relative to the threshold of the maximum volume level that the manufacturer deems safe or the listener chooses to hear.
Problems arise from the variation in the efficiency of sound transmission and hearing sensitivity across the audible frequency range. Bass sounds displace much more air than mid-range sounds to produce the same apparent loudness to the listener (FIG. 8, Graphic 1). Digital compression algorithms usually apply uniform loudness factor caps across all frequencies, for example, at 60 phons, which still permit nearly 300,000 times the displacement of air between 30 Hz at the compression cap and 3 kHz at the threshold of hearing. The sound level threshold of pain is; however, flatter than the threshold of hearing, which places audible bass sounds much closer to the pain limit than mid-range sounds. In a sealed ear canal, the pain threshold level is even lower, particularly in the bass, causing even more damage. The Occupational Safety and Health Administration (OSHA) begins requiring hearing protection at 85 dB of workplace environmental noise as prolonged exposure at that level can cause long-term damage. Early study results indicate that within a sealed ear, hearing damage begins as low as at 60 dB. An amplitude-based digital compression algorithm is too coarse a tool to adequately protect a listener's hearing.
In conclusion, no conventional earbud design to date is able to satisfactorily    1. Protect the listener's hearing from in-ear displacement based pneumatic pressures while delivering optimum, user adjustable sound quality, isolation, and ambient sound perception and directionality-sensitivity at the user's desired levels;    2. Fit each user perfectly;    3. Range in aesthetic properties from purely functional to unique, high-end customized jewelry;    4. Be fully modular to meet the servicing, fit, acoustic and aesthetic needs of the user at any point in time;    5. Provide high-fidelity audio with a stable, wireless signal;    6. Satisfactorily and variably mitigate the excessive sound levels of musical performances    7. And no existing digital compression algorithm adequately protects a listener from harmful levels of sound.
Likewise, no existing in-ear-monitor    1. allow an adjustable isolation from ambient sounds nor    2. permit an adjustable mixture of both the ambient and the electronically broadcast renditions of their performance.